Sewing machine usable in both lock stitch mode and chain stitch mode

ABSTRACT

A household type lock stitch sewing machine wherein the ordinary under thread bobbin case may be replaced by a looper or collar member which may be detachably mounted on the stud of the shuttle, whereby the single upper thread engaging the needle eye may form a series of chain stitches by using the shuttle and the looper as hook means to draw or release the thread loop in timed relation with the movement of the needle and the feed dog.

tates I; atent [191 Unite Ono et a1.

[ SEWING MACHINE USABLE IN BOTH LOCK STITCH MODE AND C STITCH MODE [75] Inventors: Takeshi Ono; Kimihiko Yamamoto,

both of Nagoya, Japan [73] Assignee: Aisin Seiki Kabushiki Kaisha,

v Kariya City, Aichi Prefi, Japan [22] Filed: Sept. 22, 1972 [21] Appl. No.: 291,838

[30] Foreign Application Priority Data Sept. 25, 1971 Japan 46-74917 [52] US. Cl. 112/168 [51] Int. Cl DOSb 1/14 [58] Field of Search 112/168, 185, 189, 190,

[56] References Cited UNITED STATES PATENTS 1,118,450 11/1914 Sibbald ..112/189 Apr. 30, 1974 3,540,390 ll/197O Eguchi 112/168 3,625,169 12/1971 Yamashita 112/168 3,720,178 3/1973 Iuanko 112/168 Primary Examiner-James R. Boler Assistant ExaminerWai M. Chan Attorney, Agent, or FirmEric H. Waters [57] ABSCT A household type lock stitch sewing machine wherein the ordinary under thread bobbin case may be replaced by a looper or collar member which may be detachably mounted on the stud of the shuttle, whereby the single upper thread engaging the needle eye may form a series of chain stitches by using the shuttle and the looper as hook means to draw or release the thread loop in timed relation with the movement of the needle and the feed dog.

8 Claims, 13 Drawing Figures PKTENTEDAMOW 3QYL3 min 2 BF 3 FIG. 2

aomse' PA 75mm 30 m4 SHEEI 3 OF 3 SEWING MACHINE USABLE IN BOTH LOCK STITCH MODE AND CHAIN STITCH MODE BACKGROUND OF THE INVENTION This invention relates to a sewing machine which is able to make both a lock stitch and a chain stitch and more particularly to additional and substitutional members which are applied to the ordinary household type lock stitch sewing machine to convert the same to a chain stitch mode of operation.

As used herein, the term upper threa refers to the single thread which is supplied from any suitable spool or other source of supply to the needle eye through the necessary tensions and feed pick-up, which need not be specifically designated here. The term under thread refers to the single thread which is supplied from a bobbin or spool received in the known bobbin case also received in the known shuttle further received on the circular race formed within the shuttle housing.

While various means have been previously employed for providing a sewing machine which can be placed in either the lock stitch mode or the chain stitch mode, none have proven to be entirely satisfactory by reason of the fact that the shuttle to be used could not be tolerated and the manufacturing work is accordingly troublesome.

It is an object of the invention to use a substantially well-known conventional household type lock stitch sewing machine, with very little or small additional and substitutional members in the operating mechanism for making the chain stitch.

It is an object of the invention to provide apparatus for producing, by a machine involving a minimum number of additional and substitutional parts, simply applied to the lock stitch sewing machine, the chain stitch.

SUMMARY OF THE INVENTION A sewing machine of the household type in which the shuttle is oscillated to produce the thread loop of the upper thread and the under thread is fed from the bobbin received in the bobbin case further received within the shuttle so that the both threads are interlocked to produce the lock stitch, characterized by the fact that the bobbin case is replaced by a looper or collar member adapted to be received within the said shuttle in the same manner as that in which the bobbin case is received whereby the lock stitch mode may be converted to the chain stitch mode of operation.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an exploded perspective view of elements of the invention;

FIG. 2 is an end elevational view, of the loop forming mechanism of the present invention;

FIG. 3 is an elevational view of the shuttle of the present invention;

FIG. 4 is a sectional view taken along the line IV IV of FIG. 2;

FIG. 5 is a sectional view similar to FIG. 4'partially cut off; and

FIGS. 6 to 13 are detail elevational views illustrating stages of the stitch-forming operations in which the needle and the shuttle are various different positions, respectively.

DESCRIPTION OF THE PREFERRED EIWBODIMENT Referring now to the embodiment of the invention shown in the drawings, the sewing machine includes a needle plate 17 in a known manner, in the base of the sewing machine. The loop forming mechanism of the present invention generally indicated by the reference character L in FIG. I is located within a cavity in the sewing machine structure vertically beneath the needle N. This cavity is upwardly covered by the needle plate 17 which acts as a support for the fabric work piece (not shown) which is fed under the needle N. The needle plate is provided with an opening 17a through which the needle N may freely reciprocate, in a known manner. The needle plate further includes slots 17b within which feed dogs 15 are free to perform a fabric advancing motion to feed fabric under the needle N in a direction parallel with the plane of FIGS. 4 and 5, that is, perpendicular to the plane of FIG. 2. The feed dogs 15 are part of the ordinary feed member of the sewing machine which is driven in a known manner (not shown) in order to advance, or feed, the fabric under the needle N.

FIGS. 1 to 5 illustrate the shuttle arrangement utilized in the illustrated embodiment of the present invention. The oscillating drive for the shuttle l of the bobbin and loop forming mechanism L includes an oscillating shaft 3 shown partially in FIG. I. In accordance with standard sewing machine construction, the oscillating shaft 3 is driven from the main shaft (not shown) through a yoke and sliding block arrangement (not shown) connected to the right end of the shaft 3. The left end of shaft 3 is connected to the bobbin and loop forming mechanism L which includes a shuttle housing 2 having a longitudinally extending sleeve 2b and supported, in a known manner, by a conventional lug (not shown) extending from the underside of the base (not shown) of the machine. The sleeve 2b receives therein the oscillating shaft 3. A collar 3a serves to hold the shaft 3 in its regular position in cooperation with shuttle driver 4 hereinbelow described. Mounted on the left end of the oscillating shaft 3 within the shuttle housing 2 is the shuttle driver 4 which drives the shuttle l to oscillate on the race portion 2a of the shuttle housing 2.

A cover ring 5 is detachably secured on the shuttle housing 2 by two arms 6 swingable about their pivots 6a. The cover ring 5 serves to hold the shuttle 1 within the annular race 2a in said shuttle housing 2, the shuttle thus being rotatively secured within said race. The positions of the arms 6 as shown in FIG. 2 correspond to their operative positions to hold the shuttle on the race while their rest (inoperative) positions are realized by outward swinging thereof as shown in FIG. 1 so that the shuttle may be removed. The operative positions of the arms 6 are attained by swinging the same until they abut against the stopper pins 5d on the end face of the cover 5 so that their notches 6b engage the pins 5d. From the under side of the outer face of the ring 5 projects a pin 50 as best shown in FIG. 1 to fit into a notch 2d formed in the edge of the housing 2 to hold the ring 5 in its angularly regular position on the internal surface of a stepped portion 20 of the housing 2.

A finger 11 is free to swing on a stepped screw 12 in a plane parallel with the plane of FIGS. 4 and 5 and it is normally spring biased to its vertical position as shown in FIG. 4 by a compressed spring 13 and a washer 12a and E shaped ring 1212. A hole 11a of the finger 11 is of sufficient size to allow the same to swing on the screw 12 through an angle in counter-clockwise direction in FIG. 5 against opposition of spring 13 in an imaginary plane in which lies the stepped screw 12.

It will be noted that the step or shoulder of the stepped screw serves to provide a better grip for the washer and the E shaped ring in cooperation with a reduced threaded portion screwed into an internally threaded hole 5e of the cover ring 5. The finger 11 is swung by the top end 15a of the feed dog 15 when the feed dog moves to the left for forward feed of the fabric as shown in FIG. 5. The spring 13 serves in cooperation with the washer to resiliently urge said finger 11 into a strictly vertical and regular position, the washer being therefore of sufficient diameter to provide an adequate size relative to the face of the finger 11. A pair of holes 1 1c and 11d of the finger 1 1 respectively receive a pair of corresponding projecting pins 5a and 5b on the end face of the cover ring 5 so that a regular angular position is always ensured, after assembly, in an imaginary plane perpendicular to the axis of the oscillating shaft 3. A pair of hooks 14 are provided on the inward face of the finger 11 relative to the shuttle l as shown in FIGS. 1 and 5. The hooks serve to catch the thread loop engaging the needle eye in a manner to be described.

A collar 7 can be mounted in place of the known bobbin case on a stud of the shuttle 1 as shown in FIGS. 4 and 5, with its axial aperture receiving the stud. A leaf spring 9 serves to resiliently urge the collar 7 into its regular position on said stud 8 with its bent end 9a resiliently engaged in annular groove 8a formed at the end of the stud 8 as seen in FIG. 4. It will be noted that the leaf spring 9 protrudes into a notch 7d formed in an end face of a flange 7c of the collar with its bent end 9a positioned to freely move therein, as best shown in FIG. 4, while the other end of the spring is secured to the collar by means of set screw 10 and its corresponding threaded hole 10a. The collar 7 is provided on its back face with a projection 7b somewhat like a crescent as shown in FIGS. 3 and 5. The contour of the projection partially fits the corresponding curved edge of the shuttle as will be seen in FIG. 3, so that'firm connection may be provided between the shuttle and the collar to rotate together. The top end face of the projection should be strictly in the same plane in which lies the back face of the shuttle as seen in section in FIG. 5 so that the thread loop may smoothly slide off when the loop is taken up by the conventional needle thread take up member (not shown). An annular groove 7a is formed in the end face of the flange 7c in concentricity to the axis of rotation of the shuttle. The top ends of hooks l4 normally sink their top ends into said annular groove so that the hooks and the collar in cooperation provide means to draw the thread loop through the fabric to the under side thereof on advancement of the fabric. An arc member. 16 is pivotally connected to the collar with both its bent ends received within corresponding apertures formed in the face of the flange 7c. The provision of the arc member serves for obtaining a better grip when the collar 7 is mounted on or removed from the stud 8, as the machine is converted to a different mode of operation, that is, either in the lock stitch mode or the chain stitch mode. It should be noted that the stud 8 receives thereon the well known conventional bobbin case not shown when the machine is placed in the lock stitch mode of operation while the collar 7 is substituted for the bobbin case when the machine is converted to the chain stitch mode of operation, as hereinbelow described in detail.

In FIG. 6, the individual parts of the loop forming mechanism L are shown in their position at the start of a chain stitch forming cycle or operation. The seizing point la of the shuttle, as shown in FIG. 6 as shaft 3 is oscillated, is presented immediately beside eye 20 of needle N. When the needle N carries thread T engaged in eye 20 through the fabric (not shown), and then started on retraction, the slack thus produced in the thread forms a loop 21. The seizing point la is so presented that it will engage within loop 21, thus formed, as will be seen in FIG. 7.

At the stage of FIG. 8, the needle N retracts from the needle plate and the fabric. At the stage of FIG. 9, the loop 21 is released from the point 1a and the finger hooks 14 engage the thread loop 21, which is prevented from sliding off by the hooks 14 on feeding of the fabric. The thread loop 21 is tensioned by the needle thread take up member. At the subsequent stages in FIGS. 10 and 11, the shuttle is in its return stroke and the feed dog 15 moves in timed relation toward the left and its top 15a abuts against the top of the finger member 11 as seen in FIG. 5 so that the finger l1 swings through an angle to the left together with its hooks 14. The pins or hooks thence are displaced out of the annular groove 7a to allow the thread loop 21 to slide off through the clearance between the top ends of the pins and the end face of the collar 7 as will be seen in FIG. 5. Before the sliding off of the loop 21, v the needle N again timingly penetrates the fabric and enters into the loop 21 as seen in FIG. 11. The individual parts of the loop forming mechanism are, at the stage of FIG. 12, in the same positions as those shown in FIG. 6 and the shuttle again starts the clockwise swing. The seizing point 1a again takes the new thread loop 22 and thereafter the new loop is handled in the same manner in which the old loop 21 was handled. A repetition of these steps, of course, produces the'chain stitch. The produced series of chain stitches is shown as best seen in FIG. 5 in solid line separately from the fabric.

From the foregoing, it will be seen that the chain stitch is produced by the use of the ordinary lock stitch household type sewing machines It should be noted that the finger and its attendant element should be removed from the cover ring 5 when the machine is placed in the lock stitch mode of operation. i i

What is claimed is:

1. A sewing machine comprising a needle plate for supporting fabric in a position to be stitched, a threaded needle for projection through fabric supported upon the needle plate, means for moving the needle to project it through and to withdraw it from the supported fabric, a feed dog to advance the fabric, means for moving said feed dog through a forward feed stroke, an oscillatable shaft, a driver, means securing said driver on the end of said shaft, means for oscillating said shaft, a shuttle housing having a circular race therein and positioned adjacent said driver, a shuttle in said housing having a seizing top adapted to catch a loop of said thread extending from said needle eye and to be oscillated on said race of said housing by said driver, a cover ring, means detachably mounting said cover ring on said housing, said cover ring covering said circular race to have the shuttle secured oscillatably on said race, a collar member, means detachably fastening said collar member to said shuttle to convert a lock stitch mode into a chain stitch mode of operation, said collar having an end face and being provided on said end face with an annular groove concentric to the rotating axis of said shuttle, a finger member, means displaceably securing said finger member on a stationary portion of the machine in the vicinity of said collar member, said finger member including at least one hook pin thereon and normally resiliently urged to engage the top end thereof in said annular groove, said finger member being so positioned that said feed dog can abut said finger member at its forward feed stroke end to move said finger whereby said hook disengages from said groove to allow the loop of said thread to slide off said collar to produce the chain stitch.

2. A sewing machine as claimed in claim 1 wherein said means detachably fastening said collar member to said shuttle comprises a stud aligned with the axis of oscillation of said shuttle, said collar'member being detachably mounted on said stud and having an axial aperture receiving said stud, the stud being adapted to support thereon the ordinary under thread bobbin case for the lock stitch mode of operation.

3. A sewing machine as claimed in claim 2 wherein said stud has an end with an annular groove therein, a leaf spring, means securing said leaf spring to said collar so that one end of said leaf spring engages said annular groove so as to hold the collar in its regular position on the stud, said collar being provided on its one end face with a projection engaging the edge of the shuttle to provide firm connection with the shuttle in rotation and having its other end face in a plane in which lies the face of the shuttle whereby the thread loop is enabled to smoothly slide 0R said other face.

4. A sewing machine as claimed in claim 1 wherein said cover ring has a screw projecting from the end face thereof and wherein the finger is loosely mounted on said screw and normally resiliently urged to cause said hook pin to engage in said annular groove in said end face of the collar, whereby said hook pin may be disengaged from said annular groove by the forward feed movement of the feed dog at its forward feed stroke end.

5. A sewing machine as claimed in claim 4 comprising a coil spring disposed between said end face of the cover ring and said finger surrounding said screw for applying the resilient action on said finger to cause the hook pin to engage said annular groove.

6. A sewing machine as claimed in claim 4 wherein the cover ring is provided with at least one pin projecting from its end face and the finger member is provided with a hole for each said pin to provide means to accurately hold the finger in a plane perpendicular to the axis of rotation of the shuttle by engagement of the hole with said pin.

7. A sewing machine as claimed in claim 1 wherein the means displaceably securing the finger member on the stationary portion of the machine comprises means supporting the finger for tilting movement towards and away from said collar member, and resilient means acting on said finger to urge the same into the position in which the hook pin resiliently engages in said annular groove.

8. A sewing machine as claimed in claim 7 wherein said means supporting the finger comprises means securing the finger member to the cover ring and allowing said tilting movement against the opposition of said 

1. A sewing machine comprising a needle plate for supporting fabric in a position to be stitched, a threaded needle for projection through fabric supported upon the needle plate, means for moving the needle to project it through and to withdraw it from the supported fabric, a feed dog to advance the fabric, means for moving said feed dog through a forward feed stroke, an oscillatable shaft, a driver, means securing said driver on the end of said shaft, means for oscillating said shaft, a shuttle housing having a circular race therein and positioned adjacent said driver, a shuttle in said housing having a seizing top adapted to catch a loop of said thread extending from said needle eye and to be oscillated on said race of said housing by said driver, a cover ring, means detachably mounting said cover ring on said housing, said cover ring covering said circular race to have the shuttle secured oscillatably on said race, a collar member, means detachably fastening said collar member to said shuttle to convert a lock stitch mode into a chain stitch mode of operation, said collar having an end face and being provided on said end face with an annular groove concentric to the rotating axis of said shuttle, a finger member, means displaceably securing said finger member on a stationary portion of the machine in the vicinity of said collar member, said finger member including at least one hook pin thereon and normally resiliently urged to engage the top end thereof in said annular groove, said finger member being so positioned that said feed dog can abut said finger member at its forward feed stroke end to move said finger whereby said hook disengages from said groove to allow the loop of said thread to slide off said collar to produce the chain stitch.
 2. A sewing machine as claimed in claim 1 wherein said means detachably fastening said collar member to said shuttle comprises a stud aligned with the axis of oscillation of said shuttle, said collar member being detachably mounted on said stud and having an axial aperture reCeiving said stud, the stud being adapted to support thereon the ordinary under thread bobbin case for the lock stitch mode of operation.
 3. A sewing machine as claimed in claim 2 wherein said stud has an end with an annular groove therein, a leaf spring, means securing said leaf spring to said collar so that one end of said leaf spring engages said annular groove so as to hold the collar in its regular position on the stud, said collar being provided on its one end face with a projection engaging the edge of the shuttle to provide firm connection with the shuttle in rotation and having its other end face in a plane in which lies the face of the shuttle whereby the thread loop is enabled to smoothly slide off said other face.
 4. A sewing machine as claimed in claim 1 wherein said cover ring has a screw projecting from the end face thereof and wherein the finger is loosely mounted on said screw and normally resiliently urged to cause said hook pin to engage in said annular groove in said end face of the collar, whereby said hook pin may be disengaged from said annular groove by the forward feed movement of the feed dog at its forward feed stroke end.
 5. A sewing machine as claimed in claim 4 comprising a coil spring disposed between said end face of the cover ring and said finger surrounding said screw for applying the resilient action on said finger to cause the hook pin to engage said annular groove.
 6. A sewing machine as claimed in claim 4 wherein the cover ring is provided with at least one pin projecting from its end face and the finger member is provided with a hole for each said pin to provide means to accurately hold the finger in a plane perpendicular to the axis of rotation of the shuttle by engagement of the hole with said pin.
 7. A sewing machine as claimed in claim 1 wherein the means displaceably securing the finger member on the stationary portion of the machine comprises means supporting the finger for tilting movement towards and away from said collar member, and resilient means acting on said finger to urge the same into the position in which the hook pin resiliently engages in said annular groove.
 8. A sewing machine as claimed in claim 7 wherein said means supporting the finger comprises means securing the finger member to the cover ring and allowing said tilting movement against the opposition of said resilient means. 